WT161 is a potent and selective inhibitor of HDAC6 (IC50:0.40 nM).

HDAC8:1430 nM, HDAC6:0.40 nM, HDAC3:51.6 nM, HDAC1:8.35 nM, HDAC2:15.4 nM

Treatment of anti-multiple myeloma (MM) cell lines with WT161 triggers the accumulation of acetylated tubulin and cell death in MM cell lines more potently than tubacin. Additionally, WT161 in combination with BTZ induces synergistic cytotoxicity and overcomes BTZ resistance in vitro[1].

WT161 significantly inhibits in vivo MCF7 cell growth, associated with downregulation of ERα, in a murine xenograft model[2].

Female NCr nu/nu mice were subcutaneously (sc) implanted with 17?-estradiol-sustained release pellets (0.18 mg, 60 day release time). Mice were inoculated sc with 5 × 10^6 MCF-7 cells suspended in 30% Matrigel. After 1 month of growth, mice with measurable tumors (> 50 mm^3) were assigned into cohorts receiving intraperitoneal WT161 daily (80 mg/kg) or into a control group receiving vehicle alone (10% DMSO, 90% PBS). Caliper measurements of the longest perpendicular tumor diameters were performed every alternate day to estimate the tumor volume, using the formula volume = ? x L x W^2. Animals were sacrificed when tumors reached 2 cm or if the mice appeared moribund. For each animal, relative tumor volume was determined by normalizing data to the baseline tumor volume for that animal at the start of treatment. Statistical significance was determined by 2-way ANOVA analysis[2].